The potential applicability of subsurface cooling in Singapore's condition was investigated. Three operation modes with different heat rejection methods were proposed. Mode 1 is an open-loop groundwater cooling system combined with cooling towers; Mode 2 is a pure groundwater cooling system without cooling towers; and Mode 3 is a surface water cooling system. Contrary to previous studies in many other areas around the world, the proposed modes are aimed for tropical areas and suitable for pure cooling purpose. The thermal effects, economic benefits, and water-consumption performances were analyzed theoretically by using the software "EnergyPlus". A conventional water-cooled air condition system was simulated as the benchmark condition. The results reveal that the proposed three modes have important advantages over the conventional air conditioning system in tropical areas such as Singapore. The amount of urban heat generated and water consumed can be significantly reduced although the electricity cost could only be marginally reduced because of the relatively high ambient temperature. A detailed comparison of the result showed that Mode 1 is a better option for application in Singapore. (C) 2012 Elsevier Ltd. All rights reserved.